Do people with net worths of $10m+ have similarly frugal lifestyles?
Or is this mainly a feature of people with net worths in the $1m-3m range?

My parents are with combined income of 7 figures now, 8 figure net worth and they live very frugally. My father drives 1997 Toyota. The wealth is mostly tied in investment and assorted properties. My mother mends socks instead of buying new ones.